Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

Krupp, N.; Lagg, A.; Livi, S.; Wilken, B.; Woch, J.; Roelof, E. C.; Williams, D. J.

doi:10.1029/2000ja900138

Cited by 102 publications

(113 citation statements)

References 53 publications

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“…In this paper we presented the periodic changes of the spectral index gamma on scales of 1.5-7 days associated with respective changes of the plasma sheet configuration throughout the whole magnetosphere. Eventually the periodic fast (order of Alfvén speed) plasma bulk flows in the magnetotail (group 3) were reported by Krupp et al (2001);, and by Kronberg et al (2008b). Therefore we suggest that the phenomena belong to one single, global-scale process which can be named Jovian substorm.…”

Section: Relation To Substormmentioning

confidence: 97%

A summary of observational records on periodicities above the rotational period in the Jovian magnetosphere

et al. 2009

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Abstract. The Jovian magnetosphere is a very dynamic system. The plasma mass-loading from the moon Io and the fast planetary rotation lead to regular release of mass from the Jovian magnetosphere and to a change of the magnetic topology. These regular variations, most commonly on several (2.5-4) days scale, were derived from various data sets obtained by different spacecraft missions and instruments ranging from auroral images to in situ measurements of magnetospheric particles. Specifically, ion measurements from the Galileo spacecraft represent the periodicities, very distinctively, namely the periodic thinning of the plasma sheet and subsequent dipolarization, and explosive mass release occurring mainly during the transition between these two phases. We present a review of these periodicities, particularly concentrating on those observed in energetic particle data. The most distinct periodicities are observed for ions of sulfur and oxygen. The periodic topological change of the Jovian magnetosphere, the associated mass-release process and auroral signatures can be interpreted as a global magnetospheric instability with analogies to the two step concept of terrestrial substorms. Different views on the triggering mechanism of this magnetospheric instability are discussed.

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Section: Relation To Substormmentioning

confidence: 97%

A summary of observational records on periodicities above the rotational period in the Jovian magnetosphere

et al. 2009

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“…k∼0.25-0.5), possibly depending on the state of expansion of the magnetosphere (e.g. Kane et al, 1995;Krupp et al, 2001). From Eq.…”

Section: Flux Transport Associated With Rotational Flow and Comparisomentioning

confidence: 99%

“…The typical plasma angular velocity in this region based on Voyager and Galileo spacecraft data corresponds roughly to k=0.6 (e.g. Kane et al, 1995;Krupp et al, 2001) such that from Eq. (3) we obtain an estimate of the rotational voltage in Jupiter's middle magnetosphere (subscript "MM") of V ROT MM ∼2.5 MV (Table 1).…”

Section: Flux Transport Associated With Rotational Flow and Comparisomentioning

confidence: 99%

“…The anisotropies of these energetic ions have been employed to study the flows in Jupiter's magnetosphere (e.g. Krupp et al, 2001;Woch et al, 2004), and have been used to identify flow bursts in the jovian tail attributed to mass-release and the Vasyliunas-cycle 948 S. V. Badman and S. W. H. Cowley: Dungey-cycle flows at Jupiter and Saturn (Woch et al, 1999;Kronberg et al, 2005). At Saturn, hot plasma injections from the magnetotail have been observed by Cassini energetic neutral atom imaging data by Mitchell et al (2005), and have been attributed to tail reconnection similar to substorms at Earth.…”

Section: Identification Of Dungey-cycle Flows In the Equatorial Magnementioning

confidence: 99%

“…The Galileo orbiter mission has been the principal source of in situ data at Jupiter (e.g. Krupp et al, 2001;Frank et al, 2002;Kronberg et al, 2005;Waldrop et al, 2005), as well as providing remote sensing observations using radio emissions (e.g. Louarn et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Significance of Dungey-cycle flows in Jupiter's and Saturn's magnetospheres, and their identification on closed equatorial field lines

2007

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Abstract. We consider the contribution of the solar winddriven Dungey-cycle to flux transport in Jupiter's and Saturn's magnetospheres, the associated voltages being based on estimates of the magnetopause reconnection rates recently derived from observations of the interplanetary medium in the vicinity of the corresponding planetary orbits. At Jupiter, the reconnection voltages are estimated to be ∼150 kV during several-day weak-field rarefaction regions, increasing to ∼1 MV during few-day strong-field compression regions.The corresponding values at Saturn are ∼25 kV for rarefaction regions, increasing to ∼150 kV for compressions. These values are compared with the voltages associated with the flows driven by planetary rotation. Estimates of the rotational flux transport in the "middle" and "outer" magnetosphere regions are shown to yield voltages of several MV and several hundred kV at Jupiter and Saturn respectively, thus being of the same order as the estimated peak Dungeycycle voltages. We conclude that under such circumstances the Dungey-cycle "return" flow will make a significant contribution to the flux transport in the outer magnetospheric regions. The "return" Dungey-cycle flows are then expected to form layers which are a few planetary radii wide inside the dawn and morning magnetopause. In the absence of significant cross-field plasma diffusion, these layers will be characterized by the presence of hot light ions originating from either the planetary ionosphere or the solar wind, while the inner layers associated with the Vasyliunas-cycle and middle magnetosphere transport will be dominated by hot heavy ions originating from internal moon/ring plasma sources. The temperature of these ions is estimated to be of the order of a few keV at Saturn and a few tens of keV at Jupiter, in both layers.

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Simulating the effect of centrifugal forces in Jupiter's magnetosphere

et al. 2014

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Jupiter's large scale size and rapid planetary rotation period combine to produce the strong centrifugal force responsible for many unique properties of its magnetosphere. It was previously proposed that this centrifugal force and nonadiabatic field line stretching could cause the observed dawn-dusk asymmetry of Jupiter's plasma sheet, which is thickest near dusk. As flux tubes rotate and stretch between noon and dusk, particles bouncing along the field gain parallel energy and create pressure anisotropy. Because bounce times can be long compared with the outward expansion timescale, particles may respond nonadiabatically, and the resulting pressure anisotropy can drive the plasma sheet to instability. We used a large-scale kinetic simulation to follow a collection of rotating particles as they move in a time-varying, rotating magnetic field designed to represent flux tube expansion in Jupiter's magnetosphere. The analysis quantifies the response of trapped particles by characterizing the pressure anisotropy and energy changes. We compare results of nonadiabatic and adiabatic outward expansions and find that the nonadiabatic case leads to a large pitch angle anisotropy and higher total energy than for adiabatic expansion. Although the calculation was not handled fully self-consistently, the results support the proposition that plasma pressure changes lead to changes in the magnetic field structure with local time. Our findings are consistent with the idea that nonadiabatic effects in Jupiter's magnetosphere contribute to field dipolarization and the observed plasma sheet thickening between noon and dusk.

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Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

Cited by 102 publications

References 53 publications

A summary of observational records on periodicities above the rotational period in the Jovian magnetosphere

A summary of observational records on periodicities above the rotational period in the Jovian magnetosphere

Significance of Dungey-cycle flows in Jupiter's and Saturn's magnetospheres, and their identification on closed equatorial field lines

Simulating the effect of centrifugal forces in Jupiter's magnetosphere

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